8d9254fc8a
From-SVN: r279813
423 lines
14 KiB
C++
423 lines
14 KiB
C++
// Functional extensions -*- C++ -*-
|
|
|
|
// Copyright (C) 2002-2020 Free Software Foundation, Inc.
|
|
//
|
|
// This file is part of the GNU ISO C++ Library. This library is free
|
|
// software; you can redistribute it and/or modify it under the
|
|
// terms of the GNU General Public License as published by the
|
|
// Free Software Foundation; either version 3, or (at your option)
|
|
// any later version.
|
|
|
|
// This library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
|
|
// Under Section 7 of GPL version 3, you are granted additional
|
|
// permissions described in the GCC Runtime Library Exception, version
|
|
// 3.1, as published by the Free Software Foundation.
|
|
|
|
// You should have received a copy of the GNU General Public License and
|
|
// a copy of the GCC Runtime Library Exception along with this program;
|
|
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
// <http://www.gnu.org/licenses/>.
|
|
|
|
/*
|
|
*
|
|
* Copyright (c) 1994
|
|
* Hewlett-Packard Company
|
|
*
|
|
* Permission to use, copy, modify, distribute and sell this software
|
|
* and its documentation for any purpose is hereby granted without fee,
|
|
* provided that the above copyright notice appear in all copies and
|
|
* that both that copyright notice and this permission notice appear
|
|
* in supporting documentation. Hewlett-Packard Company makes no
|
|
* representations about the suitability of this software for any
|
|
* purpose. It is provided "as is" without express or implied warranty.
|
|
*
|
|
*
|
|
* Copyright (c) 1996
|
|
* Silicon Graphics Computer Systems, Inc.
|
|
*
|
|
* Permission to use, copy, modify, distribute and sell this software
|
|
* and its documentation for any purpose is hereby granted without fee,
|
|
* provided that the above copyright notice appear in all copies and
|
|
* that both that copyright notice and this permission notice appear
|
|
* in supporting documentation. Silicon Graphics makes no
|
|
* representations about the suitability of this software for any
|
|
* purpose. It is provided "as is" without express or implied warranty.
|
|
*/
|
|
|
|
/** @file ext/functional
|
|
* This file is a GNU extension to the Standard C++ Library (possibly
|
|
* containing extensions from the HP/SGI STL subset).
|
|
*/
|
|
|
|
#ifndef _EXT_FUNCTIONAL
|
|
#define _EXT_FUNCTIONAL 1
|
|
|
|
#pragma GCC system_header
|
|
|
|
#include <functional>
|
|
|
|
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
|
|
{
|
|
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
|
|
|
/** The @c identity_element functions are not part of the C++
|
|
* standard; SGI provided them as an extension. Its argument is an
|
|
* operation, and its return value is the identity element for that
|
|
* operation. It is overloaded for addition and multiplication,
|
|
* and you can overload it for your own nefarious operations.
|
|
*
|
|
* @addtogroup SGIextensions
|
|
* @{
|
|
*/
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Tp>
|
|
inline _Tp
|
|
identity_element(std::plus<_Tp>)
|
|
{ return _Tp(0); }
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Tp>
|
|
inline _Tp
|
|
identity_element(std::multiplies<_Tp>)
|
|
{ return _Tp(1); }
|
|
/** @} */
|
|
|
|
/** As an extension to the binders, SGI provided composition functors and
|
|
* wrapper functions to aid in their creation. The @c unary_compose
|
|
* functor is constructed from two functions/functors, @c f and @c g.
|
|
* Calling @c operator() with a single argument @c x returns @c f(g(x)).
|
|
* The function @c compose1 takes the two functions and constructs a
|
|
* @c unary_compose variable for you.
|
|
*
|
|
* @c binary_compose is constructed from three functors, @c f, @c g1,
|
|
* and @c g2. Its @c operator() returns @c f(g1(x),g2(x)). The function
|
|
* compose2 takes f, g1, and g2, and constructs the @c binary_compose
|
|
* instance for you. For example, if @c f returns an int, then
|
|
* \code
|
|
* int answer = (compose2(f,g1,g2))(x);
|
|
* \endcode
|
|
* is equivalent to
|
|
* \code
|
|
* int temp1 = g1(x);
|
|
* int temp2 = g2(x);
|
|
* int answer = f(temp1,temp2);
|
|
* \endcode
|
|
* But the first form is more compact, and can be passed around as a
|
|
* functor to other algorithms.
|
|
*
|
|
* @addtogroup SGIextensions
|
|
* @{
|
|
*/
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Operation1, class _Operation2>
|
|
class unary_compose
|
|
: public std::unary_function<typename _Operation2::argument_type,
|
|
typename _Operation1::result_type>
|
|
{
|
|
protected:
|
|
_Operation1 _M_fn1;
|
|
_Operation2 _M_fn2;
|
|
|
|
public:
|
|
unary_compose(const _Operation1& __x, const _Operation2& __y)
|
|
: _M_fn1(__x), _M_fn2(__y) {}
|
|
|
|
typename _Operation1::result_type
|
|
operator()(const typename _Operation2::argument_type& __x) const
|
|
{ return _M_fn1(_M_fn2(__x)); }
|
|
};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Operation1, class _Operation2>
|
|
inline unary_compose<_Operation1, _Operation2>
|
|
compose1(const _Operation1& __fn1, const _Operation2& __fn2)
|
|
{ return unary_compose<_Operation1,_Operation2>(__fn1, __fn2); }
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Operation1, class _Operation2, class _Operation3>
|
|
class binary_compose
|
|
: public std::unary_function<typename _Operation2::argument_type,
|
|
typename _Operation1::result_type>
|
|
{
|
|
protected:
|
|
_Operation1 _M_fn1;
|
|
_Operation2 _M_fn2;
|
|
_Operation3 _M_fn3;
|
|
|
|
public:
|
|
binary_compose(const _Operation1& __x, const _Operation2& __y,
|
|
const _Operation3& __z)
|
|
: _M_fn1(__x), _M_fn2(__y), _M_fn3(__z) { }
|
|
|
|
typename _Operation1::result_type
|
|
operator()(const typename _Operation2::argument_type& __x) const
|
|
{ return _M_fn1(_M_fn2(__x), _M_fn3(__x)); }
|
|
};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Operation1, class _Operation2, class _Operation3>
|
|
inline binary_compose<_Operation1, _Operation2, _Operation3>
|
|
compose2(const _Operation1& __fn1, const _Operation2& __fn2,
|
|
const _Operation3& __fn3)
|
|
{ return binary_compose<_Operation1, _Operation2, _Operation3>
|
|
(__fn1, __fn2, __fn3); }
|
|
/** @} */
|
|
|
|
/** As an extension, SGI provided a functor called @c identity. When a
|
|
* functor is required but no operations are desired, this can be used as a
|
|
* pass-through. Its @c operator() returns its argument unchanged.
|
|
*
|
|
* @addtogroup SGIextensions
|
|
*/
|
|
template <class _Tp>
|
|
struct identity
|
|
: public std::_Identity<_Tp> {};
|
|
|
|
/** @c select1st and @c select2nd are extensions provided by SGI. Their
|
|
* @c operator()s
|
|
* take a @c std::pair as an argument, and return either the first member
|
|
* or the second member, respectively. They can be used (especially with
|
|
* the composition functors) to @a strip data from a sequence before
|
|
* performing the remainder of an algorithm.
|
|
*
|
|
* @addtogroup SGIextensions
|
|
* @{
|
|
*/
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Pair>
|
|
struct select1st
|
|
: public std::_Select1st<_Pair> {};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Pair>
|
|
struct select2nd
|
|
: public std::_Select2nd<_Pair> {};
|
|
|
|
/** @} */
|
|
|
|
// extension documented next
|
|
template <class _Arg1, class _Arg2>
|
|
struct _Project1st : public std::binary_function<_Arg1, _Arg2, _Arg1>
|
|
{
|
|
_Arg1
|
|
operator()(const _Arg1& __x, const _Arg2&) const
|
|
{ return __x; }
|
|
};
|
|
|
|
template <class _Arg1, class _Arg2>
|
|
struct _Project2nd : public std::binary_function<_Arg1, _Arg2, _Arg2>
|
|
{
|
|
_Arg2
|
|
operator()(const _Arg1&, const _Arg2& __y) const
|
|
{ return __y; }
|
|
};
|
|
|
|
/** The @c operator() of the @c project1st functor takes two arbitrary
|
|
* arguments and returns the first one, while @c project2nd returns the
|
|
* second one. They are extensions provided by SGI.
|
|
*
|
|
* @addtogroup SGIextensions
|
|
* @{
|
|
*/
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Arg1, class _Arg2>
|
|
struct project1st : public _Project1st<_Arg1, _Arg2> {};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Arg1, class _Arg2>
|
|
struct project2nd : public _Project2nd<_Arg1, _Arg2> {};
|
|
/** @} */
|
|
|
|
// extension documented next
|
|
template <class _Result>
|
|
struct _Constant_void_fun
|
|
{
|
|
typedef _Result result_type;
|
|
result_type _M_val;
|
|
|
|
_Constant_void_fun(const result_type& __v) : _M_val(__v) {}
|
|
|
|
const result_type&
|
|
operator()() const
|
|
{ return _M_val; }
|
|
};
|
|
|
|
template <class _Result, class _Argument>
|
|
struct _Constant_unary_fun
|
|
{
|
|
typedef _Argument argument_type;
|
|
typedef _Result result_type;
|
|
result_type _M_val;
|
|
|
|
_Constant_unary_fun(const result_type& __v) : _M_val(__v) {}
|
|
|
|
const result_type&
|
|
operator()(const _Argument&) const
|
|
{ return _M_val; }
|
|
};
|
|
|
|
template <class _Result, class _Arg1, class _Arg2>
|
|
struct _Constant_binary_fun
|
|
{
|
|
typedef _Arg1 first_argument_type;
|
|
typedef _Arg2 second_argument_type;
|
|
typedef _Result result_type;
|
|
_Result _M_val;
|
|
|
|
_Constant_binary_fun(const _Result& __v) : _M_val(__v) {}
|
|
|
|
const result_type&
|
|
operator()(const _Arg1&, const _Arg2&) const
|
|
{ return _M_val; }
|
|
};
|
|
|
|
/** These three functors are each constructed from a single arbitrary
|
|
* variable/value. Later, their @c operator()s completely ignore any
|
|
* arguments passed, and return the stored value.
|
|
* - @c constant_void_fun's @c operator() takes no arguments
|
|
* - @c constant_unary_fun's @c operator() takes one argument (ignored)
|
|
* - @c constant_binary_fun's @c operator() takes two arguments (ignored)
|
|
*
|
|
* The helper creator functions @c constant0, @c constant1, and
|
|
* @c constant2 each take a @a result argument and construct variables of
|
|
* the appropriate functor type.
|
|
*
|
|
* @addtogroup SGIextensions
|
|
* @{
|
|
*/
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Result>
|
|
struct constant_void_fun
|
|
: public _Constant_void_fun<_Result>
|
|
{
|
|
constant_void_fun(const _Result& __v)
|
|
: _Constant_void_fun<_Result>(__v) {}
|
|
};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Result, class _Argument = _Result>
|
|
struct constant_unary_fun : public _Constant_unary_fun<_Result, _Argument>
|
|
{
|
|
constant_unary_fun(const _Result& __v)
|
|
: _Constant_unary_fun<_Result, _Argument>(__v) {}
|
|
};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Result, class _Arg1 = _Result, class _Arg2 = _Arg1>
|
|
struct constant_binary_fun
|
|
: public _Constant_binary_fun<_Result, _Arg1, _Arg2>
|
|
{
|
|
constant_binary_fun(const _Result& __v)
|
|
: _Constant_binary_fun<_Result, _Arg1, _Arg2>(__v) {}
|
|
};
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Result>
|
|
inline constant_void_fun<_Result>
|
|
constant0(const _Result& __val)
|
|
{ return constant_void_fun<_Result>(__val); }
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Result>
|
|
inline constant_unary_fun<_Result, _Result>
|
|
constant1(const _Result& __val)
|
|
{ return constant_unary_fun<_Result, _Result>(__val); }
|
|
|
|
/// An \link SGIextensions SGI extension \endlink.
|
|
template <class _Result>
|
|
inline constant_binary_fun<_Result,_Result,_Result>
|
|
constant2(const _Result& __val)
|
|
{ return constant_binary_fun<_Result, _Result, _Result>(__val); }
|
|
/** @} */
|
|
|
|
/** The @c subtractive_rng class is documented on
|
|
* <a href="http://www.sgi.com/tech/stl/">SGI's site</a>.
|
|
* Note that this code assumes that @c int is 32 bits.
|
|
*
|
|
* @ingroup SGIextensions
|
|
*/
|
|
class subtractive_rng
|
|
: public std::unary_function<unsigned int, unsigned int>
|
|
{
|
|
private:
|
|
unsigned int _M_table[55];
|
|
std::size_t _M_index1;
|
|
std::size_t _M_index2;
|
|
|
|
public:
|
|
/// Returns a number less than the argument.
|
|
unsigned int
|
|
operator()(unsigned int __limit)
|
|
{
|
|
_M_index1 = (_M_index1 + 1) % 55;
|
|
_M_index2 = (_M_index2 + 1) % 55;
|
|
_M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2];
|
|
return _M_table[_M_index1] % __limit;
|
|
}
|
|
|
|
void
|
|
_M_initialize(unsigned int __seed)
|
|
{
|
|
unsigned int __k = 1;
|
|
_M_table[54] = __seed;
|
|
std::size_t __i;
|
|
for (__i = 0; __i < 54; __i++)
|
|
{
|
|
std::size_t __ii = (21 * (__i + 1) % 55) - 1;
|
|
_M_table[__ii] = __k;
|
|
__k = __seed - __k;
|
|
__seed = _M_table[__ii];
|
|
}
|
|
for (int __loop = 0; __loop < 4; __loop++)
|
|
{
|
|
for (__i = 0; __i < 55; __i++)
|
|
_M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55];
|
|
}
|
|
_M_index1 = 0;
|
|
_M_index2 = 31;
|
|
}
|
|
|
|
/// Ctor allowing you to initialize the seed.
|
|
subtractive_rng(unsigned int __seed)
|
|
{ _M_initialize(__seed); }
|
|
|
|
/// Default ctor; initializes its state with some number you don't see.
|
|
subtractive_rng()
|
|
{ _M_initialize(161803398u); }
|
|
};
|
|
|
|
// Mem_fun adaptor helper functions mem_fun1 and mem_fun1_ref,
|
|
// provided for backward compatibility, they are no longer part of
|
|
// the C++ standard.
|
|
|
|
template <class _Ret, class _Tp, class _Arg>
|
|
inline std::mem_fun1_t<_Ret, _Tp, _Arg>
|
|
mem_fun1(_Ret (_Tp::*__f)(_Arg))
|
|
{ return std::mem_fun1_t<_Ret, _Tp, _Arg>(__f); }
|
|
|
|
template <class _Ret, class _Tp, class _Arg>
|
|
inline std::const_mem_fun1_t<_Ret, _Tp, _Arg>
|
|
mem_fun1(_Ret (_Tp::*__f)(_Arg) const)
|
|
{ return std::const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); }
|
|
|
|
template <class _Ret, class _Tp, class _Arg>
|
|
inline std::mem_fun1_ref_t<_Ret, _Tp, _Arg>
|
|
mem_fun1_ref(_Ret (_Tp::*__f)(_Arg))
|
|
{ return std::mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); }
|
|
|
|
template <class _Ret, class _Tp, class _Arg>
|
|
inline std::const_mem_fun1_ref_t<_Ret, _Tp, _Arg>
|
|
mem_fun1_ref(_Ret (_Tp::*__f)(_Arg) const)
|
|
{ return std::const_mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); }
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
|
|
#endif
|
|
|